Thermoplastic foamed resins represented by styrene foam or polyethylene foam are light weight, have excellent cushioning property, heating resistance, moisture and chemical proofing. Further, being cheap, they are often used as transporting packings of fresh foods such as fishery products or vegetables, or inner, outer packings and stuffings for transporting electrical instruments, machines, etc.
Those foamed resin products are indeed expedient in use, but are inconvenient after their services because they are very bulky. In addition, being high molecular compounds, if they are burnt as waste materials, high heat is generated and it damages firing furnaces, or causes black smoke and harmful gas. Thus, consignees or receivers of products, articles etc, for example, factories, enterprises, stores and others have had difficulties in treating them.
Fish or vegetable markets where the waste materials of the foamed resins are thrown away, are installed with smelting machines as measures for treating the foamed resins. However, these types of conventional smelting machines have been very large scaled facilities and required the consummation of large quantities of kerosene and, electric power, three to four specialists for perfect smelting and generated offensive odor by thermal decomposition which polluted the environment. Besides, since the treated foamed resins are big lumps of not less than 10 kg in weight, large scaled crushers have to be used in the reproduction process, inviting higher cost.